Carbon nanotubes (CNT)
Carbon nanotubes (CNT) is one of the most spectacular materials in existence. Carbon nanotubes have an extremely high specific strength and a very high electrical and thermal conductivity, as well as excellent chemical and thermal stability. For comparison, CNT has ~20 fold higher specific strength than carbon fiber, the most common reinforcement fiber used today.
Carbon nanotubes have enormous potential in numerous applications and products. But the potential has not been unleashed yet.
Since their discovery, carbon nanotubes have received a great deal of attention due to their unique properties. In terms of tensile strength and elastic modulus, carbon nanotubes are the strongest and stiffest materials known. This strength results from the covalent sp2-bonds formed between the individual carbon atoms. In fact, carbon nanotubes are so strong that a one millimetre-thick cable made from a hypothetical, ideal CNT-polymer composite would be strong enough to lift five cars.
Carbon nanotubes are members of the fullerene structural family. Their name is derived from their long, hollow structure and the walls are formed by one-atom-thick sheets of carbon, called graphene. These sheets are rolled at specific and discrete (“chiral”) angles and the combination of the rolling angle and radius defines the nanotube properties. Carbon nanotubes are categorized as either single-walled nanotubes (SWNTs) or multi-walled nanotubes (MWNTs).
A composite material is a material made from two or more components with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components.
Thus, a composite material consists of a matrix (e.g. plastic polymer) and a reinforcement (e.g. glass fiber, carbon fiber or carbon nanotube). The reinforcement provides strength and stiffness to counteract the high flexibility and low strength of the plastic, while the plastic provides ductility to counteract the brittleness of the reinforcement. Thus, the resulting composite is relatively stiff, strong, flexible and ductile.
The maximum strength of the composite is limited by the strength of the fiber reinforcement. The ideal CNT composite should therefore have ~20 fold higher specific strength than the ideal carbon fiber composite.
Two simple problems have hindered the development of strong CNT-reinforced materials. First, the CNTs aggregate. Second, the CNTs have a very smooth surface and “slide” in a polymer matrix because of inefficient anchoring. As a result, the strength of CNT is not transferred to the composite material.
Nanocore’s technology solves both problems, i.e. both aggregation of the CNT and sliding in the composite is avoided. This is a huge step forward, not only for Nanocore, but for the materials industry as a whole: For 25 years it has been impossible to exploit CNT’s enormous strength. With Nanocore’s new approach this will now be possible.